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STRING STRETCH ?

IF YOUR STRING IS STRETCHING WHAT AFFECT WILL IT MAKE ?
WILL YOU NOTICE WHEN YOU ARE SHOOTING THAT YOU WILL HAVE TO KEEP MOVING YOUR SIGHT PIN DOWN FROM DAY TO DAY TO MAKE UP THE DIFFERNCE AND WHAT WILL IT DO TO THE POUNDAGE?
 

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Draw length will increase and so will poundage. Knock point and peep will usually go up. Don't know about moving your pins, I dont use sights.:D
 

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BT - a lot might depend on whether you're using a recurve or a compound. If a recurve / longbow, and the string stretches, the brace height gets smaller, and the arrows move faster. Unfortunately, the bow may (or may not) get get louder, or require re tuning. The nocking point may or may not move, depending on how close to center it was. Depending on the iintial brace height, it might also start slapping your wrist.

So on a recurve/longbow, the only thing for sure, is that the brace height will get shorter.

BTW - Why is you string stretching? I use B-50 Dacron, and even that is fairly stable after the initial stretch.

HP10 - Use use a peep and no sight? :confused:

Viper1 out.
 

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Viper

No, I don't use a peep. Just figured it's on the string, so it's gotta move the same direction as the knock.:) I do shoot a compound though.:D
 

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Most single cam bows with long strings that anchor to the same cam will have the nock point move down as the string gets longer.
 

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Are you shooting a twin cam or single cam. String stretch on a single cam will produce greater changes than will a twin cam.
 

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Even once a polymer string and cable set is shot in so to speak, it will still act like a rubber band and stretch various degrees from day to day. The stretch factor will depend upon temp and humidity. Strings blended with a fiber called Vectran nearly eliminates the rubber band effect. Most materials sold do not contain vectran, since it is slightly heavier, and therefore slower. So, bow companies do not sell such strings on factory bows. Check out BCY 452.
 

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russ said:
Most single cam bows with long strings that anchor to the same cam will have the nock point move down as the string gets longer.
Yes, a one-cam nock will continue to move down as the string stretches on both sides equally. Of course if twists are taken out on only one side of the string the nock can move up or down depending which side of the string is altered.

A two-cam nock will move in the opposite direction as the one-cam. As the string gets longer the nock will move up the string, unless it is centered perfectly, and then movement would be minimal, if any. This assumes that the nock is positioned above center.

A word about Vectran... Great stuff as long as it is mixed with something else. Used alone it is very dangerous. I have a one pound spool of the stuff and was making power cables with it until two of them broke at full draw on me within an eight week period. Not fun.
 

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FS560 said:
Paul, please read your first paragraph carefully.
I'm missing it? I should have used "ends" instead of "sides" but other than that I have no clue? I need to go back down in my workshop to find out where I am on this... BRB

OK, I'm back. The string on a one-cam does exactly what I stated. If you take twists out of the end of the string that contains the nock only, the nock moves up the string. If you take twists out of the inside half of the string only then the nock moves down the string. If both ends of the string lengthen equally the nock moves down as stated.

This is why you need to make adjustments to both ends of a one-cam string when on the bow.
 

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Paul, lengthening the string should be lengthening the string no matter which end of a one cam string you untwist because the idler wheel will roll and the string twist will eventually stabilize while shooting. The idler wheel section will slip on the wheel until the twist in the whole string is stabilized.
 

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When my string stretched on my G2XL, my cable also stretched. My nock point crept lower and lower until my fletching started to contact my rest. My draw length got longer and longer. But my poundage went down. It was VERY frustrating. Wayne made me a new string and cable and I'm shooting better than ever.
If you have questions about string stetch, have a set of BERRY STRINGS made from Ultra-Cam and you never have to ask that question again.
SB
 

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FS560 said:
Paul, lengthening the string should be lengthening the string no matter which end of a one cam string you untwist because the idler wheel will roll and the string twist will eventually stabilize while shooting. The idler wheel section will slip on the wheel until the twist in the whole string is stabilized.
Yes, but when you shorten or lengthen only one end of the string it moves center and changes which way the nock moves. When you only lengthen the nock end of the string the one-cam string behaves much like a two-cam string and moves up.

I could be wrong I guess, but I don't think so. I actually tested this out on my string jig this afternoon and found my original statement to be true.

My hunting bow is a one-cam, I'll test my theory out on it. Like I said I could be wrong.
 

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Experiment #2 complete. One cam bow with 3 peg adjustment on each side of the cam. Initial setting both ends of string on peg #2.

1. Moved outside of string to post #1: Nock moved 3/16" up

2. Moved inside of string also to post #1: Nock moved back 3/32" for a total upward movement of 3/32"

3. Moved outside of string back to post #2: Nock moved down another 3/16" for a total downward movement of 3/32"

The only thing I found wrong was the statement that the nock moves down when the string stretches. It actually moves up. It moves down when the string is shortened, just like a two cam.
 

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Paul why don't you try lengthening the string by untwisting it and leaving it on the Same peg rather than moving the pegs? My experience with a 96.5" PSE Carrera strings leads me to believe that a one cam string that stretches causes the nock point to move down not up!
 

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russ said:
Paul why don't you try lengthening the string by untwisting it and leaving it on the Same peg rather than moving the pegs? My experience with a 96.5" PSE Carrera strings leads me to believe that a one cam string that stretches causes the nock point to move down not up!
I moved the string on the pegs just to make the experiment go faster... The effect should be the same, and because the effect is greater by moving from peg to peg you can really see what is happening.

When you posted that the nock moves down, I questioned it to myself because I always thought the nock moved up on a one-cam as well as a two-cam. I didn't check it out.

Try it. Moving from post to post is the same as shortening or lengthening the string... And it is a quick and easy method to see stuff like this.
 

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Paul, in your original paragraph I referred to, you talked about untwisting the string, not changing pegs.

For changing pegs you are correct, however, for twisting and untwisting as you originally stated, the string will stabilize by slipping on the idler wheel.

By changing posts it is possible to reposition the whole string within the system and the idler will roll to accomodate the new setting. But the twists will not have to stabilize from side to side.
 

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Paul, when you're changing the string position on the pegs the string remains the same length and the center of the string is in the same spot. I suggest that you retry your experment by changing the length of the string rather that the position of the string mounting point.
 

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Not to doubt the effects that you have observed during your "test" but it seems that if both sides have the same measure of change then the net result should be 0. If by change the length of string the nock moves up or down it seems the same would be true during the draw cycle.

Targetnut
 

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FS560 said:
Paul, in your original paragraph I referred to, you talked about untwisting the string, not changing pegs.

For changing pegs you are correct, however, for twisting and untwisting as you originally stated, the string will stabilize by slipping on the idler wheel.

By changing posts it is possible to reposition the whole string within the system and the idler will roll to accomodate the new setting. But the twists will not have to stabilize from side to side.
Jim - Ah yes, but the stablization would take so long because of the idler serving it would drive you nuts... The peep would never settle down.

russ - I made several changes with the peg moves, so string center did change depending on what move I made. As far as twisting vs. re-peging I fail to see the difference (with the exception of having to stablize)... Moving to a longer peg has the same effect as lengthening the string, doesn't it? But, in all fairness I will try untwisting tomorrow. The problem is that untwisting will only move the nock a very small amount.
 
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